Lite DAC-AH distortion repair

[svs88]

Interesting article here, please read



"Its a resistor string DAC meaning it hasn't got the glitching problems which arise in R2R type DACs. R2R DACs (like PCM1704) need to have very precise timing between the switches operating the DAC resistor elements or glitches are the result. Resistor string DACs are inherently low in glitch. If low glitching was the reason for the better sound then that hypothesis would also fit the observation that NOS sounds better than oversampling in any given DAC.
I decided to do a little listening experiment to test out the theory that its the absence of the digital filter which contributes to the NOS sound - I built my own filter which had no pre-ringing, implemented this as 2X OS and fed it to my TDA1387 DAC. The result was it didn't sound as good as NOS, there was more greyness to the sound. So my result tends to support the view that its lower DAC glitchiness which contributes to the sound of NOS, not absence of pre-ringing. Fortunately the TDA1387 isn't an R2R, its a better performer on gltich than this architecture."

Musings on audio design - DACs, part II | LinkedIn

Nice articles. Yesterday i ordered all the needed parts for mods

 

[Kastor L]

Sorry for not so clear instructions

Pls follow to this forum post, it explains a lot:
Circuit error in Lite DAC-AH: Easy fix

I dont know how this works with TDA1387. But i am very interested about hearing your results with TDA1387 dacs

O.k., I'll check that link later, thanks.

I don't know when I will change it to TDA1387, it's not easy to remove all those TDA1543 and install sockets haha.

It seems like a lot of work just to install this early 90's chip, instead of modifying my Chinese ES9018.

I will post my results in this thread anyway.

Post the results of your passive mod as well.

 

[svs88]

O.k., I'll check that link later, thanks.

I don't know when I will change it to TDA1387, it's not easy to remove all those TDA1543 and install sockets haha.

It seems like a lot of work just to install this early 90's chip, instead of modifying my Chinese ES9018.

I will post my results in this thread anyway.

Post the results of your passive mod as well.

Yeah i know.. took 30mins just to remove two

Do you need to change some other components as well if you install tda1387 chips?

 

[abraxalito]

I don't know when I will change it to TDA1387, it's not easy to remove all those TDA1543 and install sockets haha.

Easiest is just to snip out all the 1543s. No point in fitting sockets as 1387s are SO8 (SMD in other words, need either fine wires or some DIL8-SO8 adapters).

 

[Kastor L]

LoLLL it took me a really long time just to change the AD847! I couldn't get the new socket in there, I had to keep playing around to remove the solder.

Replacing the 35 V / 2200 uF Sanyo's was quick at least, then I replaced the 25 V / 220 uF Sanyo with Elna Silmic II as well later, but I didn't notice any difference after changing the 2x 25 V I think.

In the Cyril Bateman papers Elna Silmic II have around 0.0001% distortion and they have positive reviews as well for high transparency, which is why I decided to use them.

Nichicon KZ interest me as well.

The paper in oil have positive reviews of course

Metallized x in oil or Metallized polypropylene is an alternative with the highest reviews.

I think changing to TDA1387 without any other changes should be fine as far as I'm aware.

So are you thinking to do the passive mod with paper in oil and TDA1387? That should be interesting!

I think you should consider installing sockets, then put the TDA1387 on a DIP converter, then insert them in the sockets. That way, you can always change to a different DAC chip later easily, or you can in theory stack the TDA1387 into 2x TDA1387 per socket, for sixteen in parallel in total.

Look up iBasso BUF634 to see this stacking technique.

I bought my converters and sockets from sorch_audio on Ebay, they're high quality, I'm not sure where to get the stacking style converters, if anyone knows please let me know.

 

[Kastor L]

Easiest is just to snip out all the 1543s. No point in fitting sockets as 1387s are SO8 (SMD in other words, need either fine wires or some DIL8-SO8 adapters).

You mean just cut the TDA1543 close to the surface and then solder the converters directly to the surface without any desoldering? That would save a lot of time.

Would it work to solder a 1387 directly on top of another 1387? Just wondering since I don't have any stacking converters and it says these chips don't get hot.

 

[Kastor L]

This forum says TDA1387 is the same chip as TDA1545 in a different package?

diyhifi.org/forums/viewtopic.php?t=752

 

[Kastor L]

Another person which likes the TDA1387, check the comment section

CubieNOS for Cubieboard




"I can tell you now the Philips D/A converters are of model TDA1387.

We have tried out almost everything out there and TDA1387 was unexpectedly one of the best.

/// found this chip the best sounding, the 24-bit chips aren't even close"




I noticed they have a Nos version and a resampled to 176.4 kHz version.



I can just resample with SoX via computer software, I don't quite follow what is the difference in using SoX or using an SRC chip in the DAC?

 

[abraxalito]

You mean just cut the TDA1543 close to the surface and then solder the converters directly to the surface without any desoldering? That would save a lot of time.

Yep, that's what I've done on a number of these.

Would it work to solder a 1387 directly on top of another 1387? Just wondering since I don't have any stacking converters and it says these chips don't get hot.

Yep - I've gone up to 8 chips I think, its a bit of a stretch. 6 is my normal stack size. Pays to use a multimeter to check connectivity from top to bottom, all pins can be paralleled.

TDA1545A is a slightly different chip - different digital interface and different output compliance range. Also different circuitry at pin7. The original TDA1545 (no A suffix) doesn't seem to be available nowadays but that had I2S interface. Unlike TDA1387, a DIL version of TDA1545A is available - to use it in the DAC-AH requires some jiggling with the format pins on the CS receiver chip.

 

[svs88]

Got needed parts for the modding and today completed these mods:
- Passive mod with K75-10 2.2uf capacitors.
- 680uF/35V Panasonic FC for C28 & C37 (someone mentioned that this increased a little bit bass, have to test.)
- 220uF/25V Panasonic FC for C27,
- 2200/50V uF Panasonic FC for C25 & C26 (had in storage for another project)
- Also added two missing tda1543 chips

I am very happy with the results. There is now lot of more bass, which is still accurate (i think unmodified dac-ah lacks of bass). Also the sound is now much more relaxed and easier to listen.

Here is the picture